Removing
1. Mark with paint the position of the rear wheels relative to the hub. Thanks to this, the balanced wheel after removal can be put in its place so that the balance is not disturbed. Loosen the wheel bolts without lifting the vehicle, then lift the rear of the vehicle and remove the rear wheels.
Attention! Swapping internal and external pads, as well as the pads of the left wheel for the pads of the right one, is unacceptable. It can cause uneven brake action. All overlays of one axis change at the same time.
2. Only vehicles with ASR (traction control system): remove the wear sensor wire (S10) from plug connection (S10/3x1). Do not pull on the wire while doing this.
3. Knock out retaining pins (41) from the caliper (32) suitable punch.
4. Remove the cruciform springs.
5. Remove the pads with the release lever, pliers or a screwdriver. If the pads are rusted, you need a special puller, for example, from HAZET.
Installation
Attention! Do not depress the brake pedal with the pads removed, otherwise the brake pistons will pop out of the housing. If this happened due to an oversight, remove the caliper and assemble it in a specialized workshop.
1. Clean the guide surfaces, respectively, the seating of the linings in the housing shaft with a suitable soft metal brush and a vacuum cleaner, or wipe with a cloth with alcohol. Do not use products containing mineral oil or sharp-edged tools for this.
2. Before installing the pads, feel the brake disc with your fingers for irregularities, measure the thickness of the disc.
3. Check the boot (45) for cracks. Replace a damaged boot immediately, as Penetrating dirt quickly disables the caliper. The fixed caliper brake must be removed and disassembled by a specialist workshop.
4. Reset both brake pistons with the special tool (031). A piece of wood will also come down (hammer handle), However, when doing this, be especially careful not to warp the pistons or damage the piston surfaces and dust boots.
Attention! When the pistons are pushed down, the brake fluid is squeezed out of the brake cylinders into the expansion tank. Watch the fluid level in the reservoir, it is advisable to suck out the brake fluid with a siphon.
5. For suction, use a plastic bottle containing only brake fluid. Do not use drinking bottles. Brake fluid is poisonous and must not be sucked out by mouth. Use a suction siphon. After changing the pads, the brake fluid level must not exceed the maximum mark, because due to thermal expansion, the fluid may splash out of the reservoir. The leaked fluid, dripping from the master cylinder, corrodes the paintwork, which leads to corrosion.
Attention! If the linings are worn, check the ease of movement of the pistons. To do this, insert a suitable wooden block into the caliper and ask an assistant to slowly depress the brake pedal. Brake pistons should easily come out and settle back. To check, there should be a second lining in the assembled opposite caliper.
6. Check the 20 degree piston position. In specialized workshops, a template is used for this. As a general rule, do not rotate the pistons when removing the linings! Then adjustment is not necessary.
7. Make a template from cardboard or tin according to the drawing.
8. The long side of the template should be in contact with the rear wheel caliper. The brake piston has a ledge. With this ledge, the piston must lie against the oblique side of the template, otherwise turn the piston.
9. Place the template on the lower guide plane in the caliper. The piston position is correct if the adjacent side (position at 20°) matches the piston lugs. If necessary, carefully turn the piston with a screwdriver. To prevent disc brakes from squeaking, lubricate the back of the brake lining as well as the sides of its base with a thin layer of grease.
10. Clean the lining guides in the caliper with a suitable wire brush. Do not damage the piston boot when doing this.
11. Insert pads into caliper.
12. For vehicles with ASR only: Install wear sensors on both linings. Coil the sensor wire and connect it to the plug on the caliper. Sensors may only be installed in a transparent heat-resistant version.
13. Apply cross springs and drive in retaining pins.
Attention! Pins and springs must be replaced.
14. Align the wheels so that the markings made before removing them match. Screw on the wheels. Remove the car from the supports and tighten the wheel bolts in a crosswise manner with a torque of 110 Nm.
Attention! Vigorously depress the brake pedal repeatedly until you feel strong resistance.
15. Check the brake fluid level in the reservoir, top up if necessary.
16. Gently lap in the new brake pads. To do this, repeatedly, after accelerating the car to 80 km / h, brake it to a speed of 40 km / h with slight pressure on the pedal. Allow the brakes to cool slightly between braking.
Attention! Before driving 200 km, avoid emergency braking.
17. Brake pads are a special waste and in each case, before throwing them away, you should find out if this is allowed.